Identification of Reaction Systems using Spectroscopic Measurements and Micro-reactors
01 Jan 2018-Vol. 44, pp 931-936
TL;DR: In this article, a calibration-free method is proposed to analyze spectral data obtained from micro-reactors to identify reaction kinetics, which can be applied to spectral data directly to identify the parameters of the proposed reaction kinetic model.
Abstract: Micro-reactor technology has found increasing usage in the synthesis of several organic compounds and pharmaceutical chemicals in the last decade. The main advantages of micro-reactors are good mixing characteristics, less hold-up volume of reagents and better control as compared to traditional batch reactors. Micro-reactors have recently been used in the laboratory to study the underlying reactions and develop a kinetic models. Further, it is possible to monitor reactions using in-situ spectroscopy in micro-reactors, and collect spectral data at different residence time. In this work, we propose a calibration-free method to analyse spectral data obtained from micro-reactors to identify reaction kinetics. Then, the proposed method can be applied to spectral data directly to identify the parameters of the proposed reaction kinetic model. The method is illustrated using a numerical case study of base catalyzed Knoevenagel condensation reaction system.
Citations
More filters
01 Nov 2013
TL;DR: In this paper, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed, which makes use of inline IR analysis and an automated micro-reactor system, which allowed for rapid and tight control of the operating conditions.
Abstract: Currently, kinetic data is either collected under steady-state conditions in flow or by generating time-series data in batch. Batch experiments are generally considered to be more suitable for the generation of kinetic data because of the ability to collect data from many time points in a single experiment. Now, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed. This approach makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions. The conversion/residence time profiles at several temperatures were used to fit parameters to a kinetic model. This method requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, and thus allows for the rapid generation of kinetic data.
108 citations
TL;DR: In this article, the authors present an overview of the technology along with developments and challenges associated with the combination of inkjet printing and heterogeneous catalysis, such as ink preparation, thin-film properties and real-life applications.
35 citations
TL;DR: In this paper , a high level of volume biodiesel yield was achieved from the fabricated microreactors in short residence times, compared to several studies in literature, and the highest biodiesel yields were found to be 97.9% with the Tesla-shaped microreactor at a residence time of only 4.85s only.
Abstract: • Different novel microreactors with different designs and geometries were fabricated in-house: T-shaped Y-shaped, and Tesla-shaped microreactors. • Comprehensive analysis of the performances of the fabricated microreactors for the containuous production of biodiesel were performed . • A high level of volume biodiesel yield was achieved from the fabricated microreactors in short residence times, compared to several studies in literature. • The highest biodiesel yield was found to be 97.9% with the Tesla-shaped microreactor at a residence time of 4.85s only. It was found to be 93.3% with the T-shaped microreactor and 94.3% with the Y- shaped microreactors at a residence time of 3.28s each. • Precise inline monitoring of microchannel using optical imaging showed percentage mixings of 97.6%, 97.87%, and 99.52% with T-, Y-, and Tesla- shaped microreactors, respectively. Microreactors enhance biodiesel yields due to their more efficient mixing mechanisms and faster mass transfer rates than conventional batch processes. In this investigation, microreactors with different designs and geometries (four T-shaped with different lengths, one Y-shaped, and one Tesla-shaped) have been successfully fabricated at Fab Lab Bahrain using a high-resolution CO 2 laser cutting machine. Then, the performances of these microreactors for the continuous production of biodiesel were tested and compared. The transesterification of the 9:1 molar ratio of methanol to oil was operated at a temperature of 60°C, with a 1.0 wt% NaOH catalyst. The performance of each microreactor for biodiesel synthesis was experimentally studied. The highest biodiesel yield was found to be 97.9%, with the Tesla-shaped microreactor at a residence time of only 4.85s, while the T- and Y- shaped microreactors give the highest percentage yield of 93.3% and 94.3%, respectively, with a residence time of 3.28s each. Online monitoring of the microchannel using optical imaging showed a mixing percentage of 97.6%, 97.87%, and 99.52% with T-, Y-, and Tesla- shaped microreactors, respectively, which consolidates the mixing effect's on developing the percentage yield of biodiesel.
6 citations
TL;DR: In this article, the second-order model, autocatalytic and reversible reaction were used to fit the experimental data for the esterification reaction between acetic anhydride and isoamyl alcohol.
Abstract: Uncatalyzed esterification of acetic anhydride and isoamyl alcohol has been carried out in a miniaturized intensified reactor (MIR) to develop a kinetic equation using an ideal homogenous model. The effect of reaction temperature (65 ℃ -85 ℃ ) and residence time (7.9–180.3 min) at constant molar ratio 2:1 of isoamyl alcohol to acetic anhydride were studied. The results showed that isoamyl acetate concentration production increased from 0.80 mol/L to 2.64 mol/L with residence time from 7.9 min to 180.3 min and also increased from 1.6 mol/L to 2.0 mol/L when reaction temperature increase from 65 ℃ to 85 ℃ . High conversion (>97%) of acetic anhydride was obtained in the absence of a catalyst in a microreactor system in a short residence time of 90 min as compared to days in a traditional batch reactor. This is because of the high surface-to-volume ratio of a microreactor system which promotes excellent proximate contact between reactants to allow efficient heat and mass transfer for esterification and effective mixing. Three different kinetic equations which are the second-order model, autocatalytic and reversible reaction were used to fit the experimental data. The latter kinetic model represented well for the esterification reaction between acetic anhydride and isoamyl alcohol with a good fit of 0.38 average standard error of regression between predicted concentration compare to experimental result. From the simulation result, hydrolysis of isoamyl acetate was found to be more favorable compared to acetic anhydride. This can be seen from the rate constant of reverse reaction of isoamyl acetate, where k 3 = 0.008530 L mol . s which is significantly higher compare to hydrolysis of acetic anhydride, where k 4 = 3.983 × 10 − 8 L mol . s at initial water concentration of 0.2 M. Even at different simulated initial water concentration, rate constant of hydrolysis of isoamyl acetate, k 3 was always greater than the hydrolysis of acetic anhydride, k 4 . The parameter of initial water concentration was important to be determined in which it allows to improve the fitness of the kinetic model.
4 citations
01 Jan 2023
TL;DR: In this article , the authors describe the synthesis gas and synthesis gas production methods, the advantages and disadvantages of microreactors, and finally, the modeling and simulations performed on micro-reactors.
Abstract: Syngas is a mixture of fuel gases consisting mainly of carbon monoxide, hydrogen, and carbon dioxide. Nowadays, miniature devices have attracted much attention compared with conventional devices. Various studies have been performed on the simulation and modeling of microreactors for synthetic gas. This chapter describes the synthesis gas and synthesis gas production methods, the advantages and disadvantages of microreactors, and finally, the modeling and simulations performed on microreactors. Some of the results obtained from these modeling and simulations are that with increasing temperature, the conversion of the output propane also increases, and the Peclet number to obtain Henry's law constant should be less than 0.5 also, for rapid reactions in milliseconds, the capability of thermal conductivity of the reactor wall is essential in the design of the reactor.
References
More filters
TL;DR: In this paper, the authors provide an overview of both dispersive and mixing effects in flow systems and present simple relationships for determining whether mixing or dispersion is important for a given flow system.
142 citations
01 Jan 1996
TL;DR: Signal Expressions in Raman Spectroscopy (C. Stevenson and T. Vo-Dinh), Instrumentation for Dispersive Rambusys (R. McCreery) and Fourier Transform Rambussys (P. Hendra) as discussed by the authors.
Abstract: Signal Expressions in Raman Spectroscopy (C. Stevenson & T. Vo-Dinh). Instrumentation for Dispersive Raman Spectroscopy (R. McCreery). Fourier Transform Raman Spectroscopy (P. Hendra). Micro-Raman Spectroscopy (G. Turrell & P. Dhamelincourt). Hadamard Transform Raman Spectrometry (R. Hammaker, et al.). Surface-Enhanced Raman Spectroscopy (A. Ruperez & J. Laserna). Raman Optical Activity (L. Hecht & L. Barron). Coherent Raman Spectroscopy (J. Gomez). Time-Resolved Resonance Raman Spectroscopy (M. Ondrias, et al.). Applications of Fiber Optics in NIR Raman Spectroscopy (S. Angel, et al.). Index.
132 citations
TL;DR: A method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed and makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions.
Abstract: Currently, kinetic data is either collected under steady-state conditions in flow or by generating time-series data in batch. Batch experiments are generally considered to be more suitable for the generation of kinetic data because of the ability to collect data from many time points in a single experiment. Now, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed. This approach makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions. The conversion/residence time profiles at several temperatures were used to fit parameters to a kinetic model. This method requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, and thus allows for the rapid generation of kinetic data.
129 citations
TL;DR: A novel method has been devised to derive kinetic information about reactions in microfluidic systems that is not limited to analysis by Raman spectrometry and can be used with different techniques that can be incorporated into the end of the flow path to provide rapid measurements.
Abstract: A novel method has been devised to derive kinetic information about reactions in microfluidic systems. Advantages have been demonstrated over conventional procedures for a Knoevenagel condensation ...
111 citations
01 Nov 2013
TL;DR: In this paper, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed, which makes use of inline IR analysis and an automated micro-reactor system, which allowed for rapid and tight control of the operating conditions.
Abstract: Currently, kinetic data is either collected under steady-state conditions in flow or by generating time-series data in batch. Batch experiments are generally considered to be more suitable for the generation of kinetic data because of the ability to collect data from many time points in a single experiment. Now, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed. This approach makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions. The conversion/residence time profiles at several temperatures were used to fit parameters to a kinetic model. This method requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, and thus allows for the rapid generation of kinetic data.
108 citations